the freezer compartment of our fridge has recently started producing a build up of "snow".Also, it seems to be getting noisier. Is it on its last legs?
My old fridge/freezer had a similar problem. The door didn't close properly so got it fixed and the problem went away. Although, I'm not saying that's what's wrong with yours but it may be worth a try.
The usual problem is that the adjustable feet get out of adjustment, which is why the instructions usually place an emphasis on levelling first.
On the cheaper brands, if the case twists out of shape, the door will no hang correctly. Bias the "other way" and get it all level without rocking. Rehang the door if needed so it seals correctly.